I always thought this was a Winterhalter - it isn't. It is by the Hungarian painter József Borsos. The Wikipedia article for József Borsos is here.
Debrecen is a crossroads city about 200 km almost due east of Budapest.
Countess Almasy wears a white confection in this 1852 Boros portrait.
Keywords: 1852, Borsos, Countess, Hungarian, straight coiffure, floral headdress, off shoulder scoop neckline, revers, stomacher, quarter length puffed sleeves, engageantes, full skirt, floral bodice ornament, necklace, earrings, bracelets, wrap, fur